Don't stand up
The thing is simple, you offer someone 100$ if they manage to stand up, however you will stop them by transfering your will directly to their mind and stop them from doing so.
Effect: Target is completly unable to rise from a chair
How: The hardest part is to get the victim believe you want to control his/her mind my sending your will through your finger into his/her head then you make the victim sit confortably, almost everyone hearing that will lean back relaxed and here is where you get them. the center of their weight is moved back so when you touch their forhead pretending to transmit your will in fact you simply jold your finger still not allowing them to move the center of weight and so making i impossible for them to stand up. The feeling victim gets is as if he/she was almost paralyzed